In a typical method of balancing a vehicle wheel such as a motor vehicle wheel, the wheel to be balanced is fixed to the main shaft of a balancing machine and driven in rotation by the shaft to carry out an unbalance measuring run. After the unbalance measuring run is concluded, the wheel to be balanced, in dependence on measurement results supplied in the unbalance measuring run by a measuring device, is stopped in a given angular position for a balancing operation to be carried out, by suitable deceleration of the wheel. The wheel-braking operation can be effected for example by reversing the actuation of an electric motor which serves to drive the main shaft in the measuring run. Such a method and an apparatus for carrying out the method are to be found in DE 198 44 975 C2. Methods and devices for stopping a wheel to be balanced, in a given angular position, are also described for example in DE 101 60 955 A1, DE 196 36 267 C2 and DE 196 36 298 C2.
A conventional balancing machine, for stopping or locking the main shaft which carries the wheel to be balanced, together with the wheel fixed thereon, in the rotary position which is intended for carrying out the wheel balancing operation, usually has holding brakes which are actuated by a foot pedal or by hand. When the foot pedal or a hand-actuated operating button is released, for example if the operator has to move away from the balancing machine, there is then the risk that the wheel will rotate of its own accord out of the rotary position into which it has been rotated for carrying out the balancing operation, by virtue of the effect of the static unbalance of the wheel. The static unbalance forms on the wheel a heavy location which therefore tends to rotate the wheel into the 6 o'clock position. This means that, when the operator returns to the balancing machine, he is required in any case to check the position of the wheel to see whether it has rotated autonomously in the above-indicated manner, and in most cases he is required to correct the position of the wheel. In addition, when the apparatus has a mechanical holding brake which is to be operated by the operator, there is the risk of the operator actuating the holding brake during the phase in which the wheel is decelerated from the rotary speed at which it rotates in the unbalance measuring run, to the stopped condition, in order to shorten the braking time. This means that the holding brake which is not designed to carry out that deceleration operation suffers rapid wear and quickly becomes useless.